1. Field of the Invention
The present invention relates to interposers for packaging semiconductor devices with array-type connection patterns. In particular, the present invention relates to tape-type interposers that are useful in semiconductor device assemblies and packages of reduced package height, or profile, and to semiconductor device assemblies and packages of reduced profile. The present invention also relates to methods for fabricating the tape-type interposers and to methods for forming semiconductor device assemblies and packages that include the tape-type interposers.
2. State of the Art
Conventionally, semiconductor dice have been packaged in plastic or, less commonly, in ceramic packages. Packages may support, protect, and dissipate heat from semiconductor dice. Packages may also provide external connective elements for providing power and signal distribution to and from semiconductor dice, as well as for facilitating electrical testing, such as burn-in testing and circuit evaluation, of semiconductor dice prior to or after assembly thereof with higher-level components, such as carrier substrates or circuit boards.
The ever-decreasing sizes of electronic devices, such as cellular telephones, handheld computers, and portable computers, have driven the need for semiconductor device assemblies and packages with ever-decreasing profiles, as well as the need for semiconductor device assemblies and packages that consume ever-decreasing amounts of the surface areas, or “real estate”, of carrier substrates, such as circuit boards.
The need for semiconductor device assemblies and packages that consume ever-decreasing amounts of real estate has been met by use of external connection technologies, such as so-called “flip-chip” connections, in which a semiconductor device is positioned over a carrier therefore in an inverted orientation with contact pads (e.g., bond pads of a bare semiconductor die or contacts of a semiconductor device assembly or package) of the semiconductor device and corresponding terminal pads of the carrier in alignment with one another. Flip-chip type connections provide the desired number of connections to a semiconductor device without requiring that an assembly or package that includes the semiconductor device have peripheral edges that extend a substantial distance beyond the peripheral edges of the semiconductor device. This type of semiconductor device assembly or package is typically referred to as a “grid array” package (e.g., a ball grid array (BGA) package or pin grid array (PGA) package) due to the arrangement of input and output contacts thereof in a grid array connection pattern. Such contact pad arrangements facilitate the use of a greater number of connections than would otherwise be possible when contact pads are arranged only along the periphery of an interposer.
Grid array semiconductor device assemblies and packages typically include an interposer to which one or more semiconductor dice may be secured and electrically connected. A substrate of the interposer may be formed from a variety of different, typically electrically insulative or insulator-coated materials, including flexible materials, such as polymer (e.g., polyimide) films or tapes, and rigid materials, such as silicon, glass, ceramic, or organic materials (e.g., FR-4 resin).
Interposers for use in grid array assemblies and packages also typically include conductive traces that extend between first and second sets of contacts, with each of the foregoing being carried by the interposer substrate. Contacts of a first set are electrically connectable to corresponding bond pads of a semiconductor die. Contacts of a second set are configured for making external electrical connections to other electronic components, such as circuit boards or other semiconductor devices. When the first and second sets of contacts are on opposite sides of the interposer, conductive vias may be positioned along one or more conductive traces to facilitate communication between contact pads of the first set and their corresponding contact pads of the second set. The first and second sets of contact pads are arranged in such a way as to redistribute the locations of the bond pads of a semiconductor device secured to the interposer. Such redistribution may provide for a contact pad arrangement that is more desirable than the arrangement of bond pads on the semiconductor device, for a contact pad that is more useful than the bond pad arrangement in flip-chip applications, for increased spacing or pitch between adjacent contact pads relative to that between corresponding, adjacent bond pads of the semiconductor device, or some combination of these features.
When such an interposer is assembled with a semiconductor device, the contact pads of the first group are typically connected to corresponding bond pads of the semiconductor device by way of discrete conductive elements, such as bond wires, conductive tape-automated bond (TAB) elements carried upon a flexible, dielectric substrate, or by so-called “flip-chip” bonding techniques, which employ conductive structures such as balls, bumps, columns, or other structures formed from conductive material, such as metal, metal alloy (e.g., solder), conductive or conductor-filled polymer, anisotropically (i.e., z-axis) conductive elastomer, or the like.
An interposer-semiconductor device assembly may communicate with electronic components external thereto by way of external conductive elements, such as conductive balls, bumps, columns, pins, or other structures, that extend from contact pads of the second set. When solder balls are employed, the connection pattern of such a semiconductor device assembly is termed a “ball grid array” (BGA) connection pattern or a “fine ball grid array” (FBGA) connection pattern, depending upon the spacing or pitch between adjacent solder balls. Similarly, when pins are used as the external conductive elements of such an assembly, the connection pattern of the assembly may be referred to as a “pin grid array” (PGA) connection pattern.
Conventionally, the thicknesses of such assemblies are defined by the cumulative thicknesses of the interposer, the adhesive material securing a semiconductor device thereto, the semiconductor device, the distance bond wires protrude above an active surface of the semiconductor device, and the distance external conductive elements extend from the interposer.
Several interposer designs have been developed to address the need for semiconductor device assemblies and packages of ever-decreasing profiles. For example, some rigid interposers include recesses for receiving all or part of a semiconductor device. The recesses of such interposers may also be configured to receive all or part of the discrete conductive elements (e.g., bond wires) that electrically connect bond pads of a semiconductor device to corresponding contact pads of the interposer. The profiles of grid array-type assemblies or packages including such interposers are typically defined by a combination of the thickness of the interposer, the distance that discrete conductive elements protrude above a surface of the interposer, and the height of conductive structures protruding from an opposite surface of the interposer. While these grid array packages are thinner than their predecessors by an amount equal to the full or partial thicknesses of the semiconductor devices and adhesive layers thereof, it is difficult, if not impossible, to further decrease their profiles.
Accordingly, there are needs for semiconductor device assemblies and packages having reduced profiles, as well as for an interposer configured to impart an assembly or package including the same with a thinner profile.